As part of the 20-year contracts, the companies will install approximately 1,800 behind-the-meter energy storage units in Orange County starting early 2016.
NRG Energy West Region president John Chillemi said: "We look forward to combining our experience in delivering customer-driven clean energy solutions with Ice Energy and their innovative technology to provide clean and reliable distributed energy storage products to this bellwether state."
Work under the contract is subject to approval from the California Public Utilities Commission.
The Ice Bear, which is integrated to standard rooftop commercial AC units, is designed to freeze ice when power demand is low.
The stored ice will be used to provide cooling instead of power-intensive AC compressors. Each Ice Bear is expected to reduce CO2 emissions by up to 4t a year.
Ice Energy CEO Mike Hopkins said: "Energy storage, particularly the distributed and efficient storage capacity provided by our Ice Bears, reduces reliance on fossil fuels and helps better integrate renewable energy sources into a smarter electric grid."
Ice Energy has so far installed around 1,000 Ice Bear units in more than 40 utility service territories across the country.
